pepper: parse context creation attrib list on the plugin side

gpu/command_buffer_traits.gypi

 # Copyright (c) 2016 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 {
   'dependencies': [
     '../base/base.gyp:base',
     '../ipc/ipc.gyp:ipc',
     '../third_party/khronos/khronos.gyp:khronos_headers',
+    '../ui/gfx/ipc/geometry/gfx_ipc_geometry.gyp:gfx_ipc_geometry',
+    'command_buffer/command_buffer.gyp:gles2_utils',
   ],
   'include_dirs': [
     '..',
   ],
   'sources': [
     'ipc/common/gpu_command_buffer_traits.cc',
     'ipc/common/gpu_command_buffer_traits.h',
     'ipc/common/memory_stats.cc',
     'ipc/common/memory_stats.h',
     'ipc/common/surface_handle.h',
@@ skipping 11 matching lines @@
     ['OS=="android"', {
       'sources': [
         'ipc/common/android/surface_texture_manager.cc',
         'ipc/common/android/surface_texture_manager.h',
         'ipc/common/android/surface_texture_peer.cc',
         'ipc/common/android/surface_texture_peer.h',
       ]
     }]
   ],
 }